The present invention relates to an automatic regulator of intake air in a tank and, more specifically, it relates to such a regulator of the type normally used for feeding a distribution plant with compressed air.
In industrial applications, installations for the production of compressed air are well known. Such installations are constituted essentially by an oil bath spin compressor, an air/oil separator tank, a tank for the accumulation of pressurized air and a minimum pressure valve. The minimum pressure valve is inserted in the conduit between the separator tank and the accumulation tank and other valves (thermostatic, pressurestats or safety).
In particular, normally on top of the installation, there is present a valve which has the function of intercepting the passage of air from the exterior to the interior of the circuit. This valve is normally called an intake regulator and a particular constructive form is disclosed in Italian patents Nos. 85521/A/90, No. 1270553 and No. 1270769 filed in the name of the applicant herein. The valve is applied at the orifice of the spin compressor intake and has the function of regulating or interrupting the flow of intake air from the exterior as a function of the requirements of the operation of the installation.
The intake regulator is constituted essentially by a slider which is provided with an alternating rectilinear motion, caused by the balancing effect between the pressure generated by the aspired exterior air and the pressure contrary to the preceeding one generated by the pressurized air from the circuit.
In the present state of the art, the operation of the intake regulator is only possible using sufficiently complex circuits which use mechanical parts put in motion by means of springs and to ensure tightness with gaskets and worked seats, all matters requiring a complex construction and high cost of the regulator.
In addition, normally, when in the pressurized air accumulation tank the desired pressure is reached, the air which is produced by the compressor which continues to function at idle is directly discharged to the atmosphere with the consequent effects of pollution.
An object of the present invention is to provide an automatic external air intake regulator with which it is possible to reduce energy consumption and pollution, whereby it is possible in operating at idle to reach in the separator tank a minimum pressure and possible to use again almost totally the pressurized air which is not stored in the accumulation tank.
A further object of the invention is to provide an automatic external air intake regulator which is of substantially simplified construction because it is constituted by a monobloc in the interior of which there are only two conduits, the monobloc being without seals and elastic devices, such as springs, because the slider is advantageously supported by an air cushion.
Still another object of this invention is to provide an automatic external air intake regulator which requires for its regulation only one electrovalve.
Still another object of this invention is to provide an automatic external air intake regulator in which it is possible to generate a counterpressure capable of balancing the negative pressure which is generated on the mechanism of the screw pump during idling.